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<title>97_开发规范</title><link href='https://fonts.loli.net/css?family=Open+Sans:400italic,700italic,700,400&subset=latin,latin-ext' rel='stylesheet' type='text/css' /><style type='text/css'>html {overflow-x: initial !important;}:root { --bg-color:#ffffff; --text-color:#333333; --select-text-bg-color:#B5D6FC; --select-text-font-color:auto; --monospace:"Lucida Console",Consolas,"Courier",monospace; }
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table{
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    height: 2px;
    padding: 0;
    margin: 16px 0;
    background-color: #e7e7e7;
    border: 0 none;
    overflow: hidden;
    box-sizing: content-box;
}

li p.first {
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}
ul,
ol {
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ul:first-child,
ol:first-child {
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ul:last-child,
ol:last-child {
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}
blockquote {
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blockquote blockquote {
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    word-break: initial;
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table tr {
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    margin: 0;
    padding: 0;
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table tr:nth-child(2n),
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table tr th {
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    border-bottom: 0;
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table tr td {
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    margin-top: 15px;
    padding-top: 8px;
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<div id='write'  class=''><h2><a name="开发规范" class="md-header-anchor"></a><span>开发规范</span></h2><p>&nbsp;</p><h3><a name="编码规范" class="md-header-anchor"></a><span>编码规范</span></h3><p><span>目前编码主要涉及service、web，其中service是强编码规范要求，使用checkstyle插件，在打包时校验编码规范，不满足规范时，将打包失败，在控制台输出异常信息。</span></p><ul><li><span>编码规范验证失败，异常信息：</span></li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[16] (javadoc) SummaryJavadoc: Javadoc的第一句缺少一个结束时期。</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[21] (javadoc) JavadocStyle: Javadoc 首句应以句号结尾。</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[21] (javadoc) SummaryJavadoc: Javadoc的第一句缺少一个结束时期。</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[26,5] (whitespace) NoWhitespaceBefore: ';' 前不应有空格。</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[29,22] (misc) FinalParameters: 参数： subCode 应定义为 final 的。</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">[ERROR] src\main\java\com\wlb365\example\message\ExampleErrorEnum.java:[33,5] (javadoc) JavadocMethod: 缺少 Javadoc 。</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 295px;"></div><div class="CodeMirror-gutters" style="display: none; height: 295px;"></div></div></div></pre><p><span>web端编码规范参考service规范，但web端为非强制规范，也就是说编码不规范，不影响正常打包运行。</span></p><ul><li><span>团队统一定义标记：</span></li></ul><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="java"><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang="java"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-comment">//TODO  待处理的问题；</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-comment">//FIXME 已知有问题的代码；</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp;<span class="cm-comment">//HACK 不得不采用的粗糙的解决方案</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 68px;"></div><div class="CodeMirror-gutters" style="display: none; height: 68px;"></div></div></div></pre><h4><a name="编码规范是什么" class="md-header-anchor"></a><span>编码规范是什么？</span></h4><p><span>自己编码体验吧，打不了包，控制台自然报出来不满足相应规范，照着提示改就可以了。</span></p><p>&nbsp;</p><h3><a name="测试规范" class="md-header-anchor"></a><span>测试规范</span></h3><ol start='' ><li><p><span>【强制】单元测试：在开发service时，每开发完一个功能，就要在项目test包下，开发对应的单元测试案例，单元测试样案可参考example-service项目。</span></p><blockquote><p><span>说明：目的是测试微服务代码运行情况</span></p></blockquote></li><li><p><span>【强制】整体测试：在service开发完成后，在test工程中编写对应的test项目，可参考example-test项目</span></p><blockquote><p><span>说明：目的是测试微服务与网关集成后的整体性测试</span></p></blockquote></li><li><p><span>【建议】测试案例编写时，尽量考虑周全，把能想到的正例、反例代码都编写了</span></p></li><li><p><span>代码覆盖率测试，还未正式使用，打算使用cobertura插件进行测试</span></p></li></ol><blockquote><p><span>说明：mvn cobertura:cobertura</span></p></blockquote><h3><a name="版本控制git）" class="md-header-anchor"></a><span>版本控制（Git）</span></h3><p><span>版本控制我们采用Git工具，代码托管在Gitee上。</span></p><ol start='' ><li><span>【强制】每天下班前，务必提交当天代码；</span></li><li><span>【强制】版本库中应只提交有效代码、文档，以及相应脚本等源码相关文件，切记不可提交任何本地配置相关文件；</span></li><li><span>【强制】注释、注释、注释，提交代码时，必须写注释，并且注释要和代码对应</span></li><li><span>【强制】相关功能，一次提交；一次提交，一个功能（一个Bug）。提交不要过多，开发完一个功能，或者修改完一个Bug，就将相应代码提交。</span></li></ol><p>&nbsp;</p><h3><a name="数据库规范" class="md-header-anchor"></a><span>数据库规范</span></h3><h4><a name="建表规范" class="md-header-anchor"></a><span>建表规范</span></h4><ol start='' ><li><span>【强制】表达是与否概念的字段，必须使用is_xxx的方式命名，数据类型是unsigned tinyint（ 1表示是，0表示否）</span></li></ol><blockquote><p><span>说明：任何字段如果为非负数，必须是</span><code>unsigned</code>
<span>正例：表达逻辑删除的字段名</span><code>is_deleted</code><span>，1表示删除，0表示未删除</span></p></blockquote><ol start='2' ><li><span>【强制】表名、字段名必须使用小写字母或数字，禁止出现数字开头，禁止两个下划线中间只出现数字。数据库字段名的修改代价很大，因为无法进行预发布，所以字段名称需要慎重考虑</span></li></ol><blockquote><p><span>说明：MySQL在Windows下不区分大小写，但在Linux下默认是区分大小写。因此，数据库名、表名、字段名，都不允许出现任何大写字母，避免节外生枝</span>
<span>正例：aliyun_admin，rdc_config，level3_name</span>
<span>反例：AliyunAdmin，rdcConfig，level_3_name</span></p></blockquote><ol start='3' ><li><span>【强制】表名不使用复数名词</span></li></ol><blockquote><p><span>说明：表名应该仅仅表示表里面的实体内容，不应该表示实体数量，对应于DO类名也是单数形式，符合表达习惯</span></p></blockquote><ol start='4' ><li><span>【强制】禁用保留字，如</span><code>desc</code><span>、</span><code>range</code><span>、</span><code>match</code><span>、</span><code>delayed</code><span>等，请参考MySQL官方保留字</span></li></ol><ol start='5' ><li><span>【强制】主键索引名为pk</span><em><span>字段名；唯一索引名为uk</span></em><span>字段名；普通索引名则为idx_字段名</span></li></ol><blockquote><p><span>说明：pk_ 即primary key；uk_ 即 unique key；idx_ 即index的简称</span></p></blockquote><ol start='6' ><li><span>【强制】小数类型为decimal，禁止使用float和double</span></li></ol><blockquote><p><span>说明：float和double在存储的时候，存在精度损失的问题，很可能在值的比较时，得到不正确的结果。如果存储的数据范围超过decimal的范围，建议将数据拆成整数和小数分开存储</span></p></blockquote><ol start='7' ><li><span>【强制】如果存储的字符串长度几乎相等，使用char定长字符串类型</span></li></ol><ol start='8' ><li><span>【强制】varchar是可变长字符串，不预先分配存储空间，长度不要超过5000，如果存储长度大于此值，定义字段类型为text，独立出来一张表，用主键来对应，避免影响其它字段索引效率</span></li></ol><ol start='9' ><li><span>【强制】表必备三字段：id, gmt_create, gmt_modified</span></li></ol><blockquote><p><span>说明：其中id必为主键，类型为unsigned bigint、单表时自增、步长为1。gmt_create, gmt_modified的类型均为datetime类型，前者现在时表示主动创建，后者过去分词表示被动更新</span></p></blockquote><ol start='10' ><li><span>【推荐】表的命名最好是加上“业务名称_表的作用”</span></li></ol><blockquote><p><span>正例：alipay_task / force_project / trade_config </span></p></blockquote><ol start='11' ><li><span>【推荐】库名与应用名称尽量一致</span></li></ol><ol start='12' ><li><span>【推荐】如果修改字段含义或对字段表示的状态追加时，需要及时更新字段注释</span></li></ol><ol start='13' ><li><p><span>【推荐】字段允许适当冗余，以提高查询性能，但必须考虑数据一致。冗余字段应遵循：</span></p><ul><li><span>不是频繁修改的字段</span></li><li><span>不是varchar超长字段，更不能是text字段</span></li></ul></li></ol><blockquote><p><span>正例：商品类目名称使用频率高，字段长度短，名称基本一成不变，可在相关联的表中冗余存储类目名称，避免关联查询</span></p></blockquote><ol start='14' ><li><span>【推荐】单表行数超过500万行或者单表容量超过2GB，才推荐进行分库分表</span></li></ol><blockquote><p><span>参考：如果预计三年后的数据量根本达不到这个级别，请不要在创建表时就分库分表</span></p></blockquote><ol start='15' ><li><span>【参考】合适的字符存储长度，不但节约数据库表空间、节约索引存储，更重要的是提升检索速度</span></li></ol><blockquote><p><span>正例：如下表，其中无符号值可以避免误存负数，且扩大了表示范围</span></p><figure><table><thead><tr><th><span>对象</span></th><th><span>年龄区间</span></th><th><span>类型</span></th><th><span>字节</span></th></tr></thead><tbody><tr><td><span>人</span></td><td><span>150岁之内</span></td><td><span>unsigned tinyint</span></td><td><span>1</span></td></tr><tr><td><span>龟</span></td><td><span>数百岁</span></td><td><span>unsigned smallint</span></td><td><span>2</span></td></tr><tr><td><span>恐龙化石</span></td><td><span>数千万岁</span></td><td><span>unsigned int</span></td><td><span>4</span></td></tr><tr><td><span>太阳</span></td><td><span>约50亿年</span></td><td><span>unsigned bigint</span></td><td><span>8</span></td></tr></tbody></table></figure></blockquote><h4><a name="sql语句规范" class="md-header-anchor"></a><span>SQL语句规范</span></h4><h2><a name="sql语句" class="md-header-anchor"></a><span>SQL语句</span></h2><ol start='' ><li><span>【强制】不要使用count(列名)或count(常量)来替代count(</span><em><span>)，count(</span></em><span>)是SQL92定义的标准统计行数的语法，跟数据库无关，跟NULL和非NULL无关</span></li></ol><ol start='2' ><li><span>【强制】count(distinct col) 计算该列除NULL之外的不重复行数，注意 count(distinct col1, col2) 如果其中一列全为NULL，那么即使另一列有不同的值，也返回为0</span></li></ol><ol start='3' ><li><span>【强制】当某一列的值全是NULL时，count(col)的返回结果为0，但sum(col)的返回结果为NULL，因此使用sum()时需注意NPE问题</span></li></ol><blockquote><p><span>正例：可以使用如下方式来避免sum的NPE问题</span></p><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">SELECT IF(ISNULL(SUM(g)),0,SUM(g)) FROM table;</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 23px;"></div><div class="CodeMirror-gutters" style="display: none; height: 23px;"></div></div></div></pre></blockquote><ol start='4' ><li><p><span>【强制】使用</span><code>ISNULL()</code><span>来判断是否为NULL值。 说明：NULL与任何值的直接比较都为NULL</span></p><ul><li><code>NULL&lt;&gt;NULL</code><span>的返回结果是NULL，而不是</span><code>false</code><span>。  </span></li><li><code>NULL=NULL</code><span>的返回结果是NULL，而不是</span><code>true</code><span>。  </span></li><li><code>NULL&lt;&gt;1</code><span>的返回结果是NULL，而不是</span><code>true</code><span>。</span></li></ul></li></ol><ol start='5' ><li><span>【强制】 在代码中写分页查询逻辑时，若count为0应直接返回，避免执行后面的分页语句</span></li></ol><ol start='6' ><li><span>【强制】不得使用外键与级联，一切外键概念必须在应用层解决</span></li></ol><blockquote><p><span>说明：以学生和成绩的关系为例，学生表中的student_id是主键，那么成绩表中的student_id则为外键。如果更新学生表中的student_id，同时触发成绩表中的student_id更新，即为级联更新。外键与级联更新适用于单机低并发，不适合分布式、高并发集群；级联更新是强阻塞，存在数据库更新风暴的风险；外键影响数据库的插入速度</span></p></blockquote><ol start='7' ><li><span>【强制】禁止使用存储过程，存储过程难以调试和扩展，更没有移植性</span></li></ol><ol start='8' ><li><span>【强制】数据订正（特别是删除、修改记录操作）时，要先select，避免出现误删除，确认无误才能执行更新语句</span></li></ol><ol start='9' ><li><span>【推荐】in操作能避免则避免，若实在避免不了，需要仔细评估in后边的集合元素数量，控制在1000个之内</span></li></ol><ol start='10' ><li><span>【参考】如果有全球化需要，所有的字符存储与表示，均以utf-8编码，注意字符统计函数的区别</span></li></ol><blockquote><p><span>说明：SELECT LENGTH(&quot;轻松工作&quot;)； 返回为12</span>
<span>SELECT CHARACTER_LENGTH(&quot;轻松工作&quot;)； 返回为4</span>
<span>如果需要存储表情，那么选择utf8mb4来进行存储，注意它与utf-8编码的区别</span></p></blockquote><ol start='11' ><li><span>【参考】 TRUNCATE TABLE 比 DELETE 速度快，且使用的系统和事务日志资源少，但TRUNCATE无事务且不触发trigger，有可能造成事故，故不建议在开发代码中使用此语句</span></li></ol><blockquote><p><span>说明：TRUNCATE TABLE 在功能上与不带 WHERE 子句的 DELETE 语句相同</span></p></blockquote><p>&nbsp;</p><h3><a name="日志规范" class="md-header-anchor"></a><span>日志规范</span></h3><ol start='' ><li><span>【强制】应用中不可直接使用日志系统（Log4j、Logback）中的API，而应依赖使用日志框架SLF4J中的API，使用门面模式的日志框架，有利于维护和各个类的日志处理方式统一。 </span></li></ol><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">import org.slf4j.Logger;</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">import org.slf4j.LoggerFactory;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">private static final Logger logger = LoggerFactory.getLogger(Abc.class); &nbsp;</span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 68px;"></div><div class="CodeMirror-gutters" style="display: none; height: 68px;"></div></div></div></pre><ol start='2' ><li><span>【强制】日志文件推荐至少保存15天，因为有些异常具备以“周”为频次发生的特点。</span></li></ol><ol start='3' ><li><span>【强制】应用中的扩展日志（如打点、临时监控、访问日志等）命名方式：appName_logType_logName.log。logType:日志类型，推荐分类有stats/monitor/visit等；logName:日志描述。这种命名的好处：通过文件名就可知道日志文件属于什么应用，什么类型，什么目的，也有利于归类查找。</span></li></ol><blockquote><p><span>正例：mppserver应用中单独监控时区转换异常，如：mppserver_monitor_timeZoneConvert.log</span>
<span>说明：推荐对日志进行分类，如将错误日志和业务日志分开存放，便于开发人员查看，也便于通过日志对系统进行及时监控。</span></p></blockquote><ol start='4' ><li><span>【强制】对trace/debug/info级别的日志输出，必须使用条件输出形式或者使用占位符的方式。</span></li></ol><blockquote><p><span>说明：logger.debug(&quot;Processing trade with id: &quot; + id + &quot; and symbol: &quot; + symbol); 如果日志级别是warn，上述日志不会打印，但是会执行字符串拼接操作，如果symbol是对象，会执行toString()方法，浪费了系统资源，执行了上述操作，最终日志却没有打印。 </span>
<span>正例：</span></p></blockquote><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  //条件</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  if (logger.isDebugEnabled()) { &nbsp; &nbsp;</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  logger.debug("Processing trade with id: " + id + " and symbol: " + symbol); &nbsp; </span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  }</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  //占位符</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> &nbsp; &nbsp; &nbsp;  logger.debug("Processing trade with id: {} and symbol : {} ", id, symbol); </span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="">​</span></span></pre></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 227px;"></div><div class="CodeMirror-gutters" style="display: none; height: 227px;"></div></div></div></pre><ol start='5' ><li><span>【强制】避免重复打印日志，浪费磁盘空间，务必在log4j.xml中设置additivity=false</span></li></ol><blockquote><p><span>正例：</span></p></blockquote><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">&lt;logger name="com.taobao.dubbo.config" additivity="false"&gt;</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 23px;"></div><div class="CodeMirror-gutters" style="display: none; height: 23px;"></div></div></div></pre><ol start='6' ><li><span>【强制】异常信息应该包括两类信息：案发现场信息和异常堆栈信息。如果不处理，那么通过关键字throws往上抛出。</span></li></ol><blockquote><p><span>正例：</span></p></blockquote><pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang=""><div class="CodeMirror cm-s-inner CodeMirror-wrap" lang=""><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 0px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation"><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;">logger.error(各类参数或者对象toString + "_" + e.getMessage(), e);</span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 23px;"></div><div class="CodeMirror-gutters" style="display: none; height: 23px;"></div></div></div></pre><ol start='7' ><li><span>【推荐】谨慎地记录日志。生产环境禁止输出debug日志；有选择地输出info日志；如果使用warn来记录刚上线时的业务行为信息，一定要注意日志输出量的问题，避免把服务器磁盘撑爆，并记得及时删除这些观察日志。</span></li></ol><blockquote><p><span>说明：大量地输出无效日志，不利于系统性能提升，也不利于快速定位错误点。记录日志时请思考：这些日志真的有人看吗？看到这条日志你能做什么？能不能给问题排查带来好处？</span></p></blockquote><ol start='8' ><li><span>【推荐】可以使用warn日志级别来记录用户输入参数错误的情况，避免用户投诉时，无所适从。如非必要，请不要在此场景打出error级别，避免频繁报警。</span>
<span>说明：注意日志输出的级别，error级别只记录系统逻辑出错、异常或者重要的错误信息。</span></li></ol><p>&nbsp;</p><p>&nbsp;</p></div>
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